Surface plasmon-polaritons, referred herein simply as plasmon-polaritons, are transverse-magnetic (TM) polarized electromagnetic surface waves coupled to free electron oscillations at the interface between a dielectric characterized by a (possibly complex) permittivity with positive real part and a medium (typically a metal) characterized by a permittivity with negative real part (e.g., Au, Ag, Cu, and Al at visible and infrared wavelengths). Plasmon-polaritons exhibit interesting properties that find applications in a broad range of scientific fields. However, a fundamental problem that imposes limitations to many of these applications is the large propagation loss of plasmon-polaritons at visible and near-infrared wavelengths, which results from energy dissipation in the media in which they propagate.
The amplification of plasmon-polariton waves has been proposed as a route to mitigate or even eliminate their intrinsic losses, and considerable effort has been devoted to demonstrate amplification and lasing with plasmon-polaritons.
This section provides background information related to the present disclosure which is not necessarily prior art.